The present invention relates to an injection/aspiration device and a cartridge vial for use therewith for medical and research purposes and more particularly to a device designed for injecting medicines and other fluids into human beings and other subjects using a hollow injection needle. Both the injection/aspiration and cartridge vial components of the invention are also configured to aspirate blood and/or other fluids.
In the conventional medical procedure for injecting medicines or for aspirating blood or fluids, a syringe with a hollow injection/aspiration needle, such as a standard hypodermic needle, is used. Needles are repugnant to many patients, particularly those who must have regular injections of medicine or blood samples taken. Among these are elderly patients and people who must have daily injections of insulin or other drugs. Similarly, pediatric patients are particularly afraid of needles. Exposed or visible needles are undesirable because they create fear and apprehension in many subjects.
Another problem in the medical field is that of the communication of infectious diseases caused by used needles and syringes and fluids therefrom coming into contact with doctors, nurses, or other medical personnel. Needle tips often remain exposed after aspiration of a fluid or blood from a subject, or after injection of a medicine into a subject and medical personnel are sometimes accidentally pricked with such tips. This problem is particularly acute in situations where a syringe and needle have been contaminated with particularly virulent organisms such as the AIDS virus or the hepatitis virus. The risk of puncture with a contaminated needle point is of particular concern after an injection because a finger, hand or other part of the person administering the injection is typically in close physical proximity to the needle during its removal from the subject's tissues, during replacement of a needle or the needle cover or during removal of the needle from a syringe for disposal.
There is also danger of such exposures to personnel, such as maintenance people, other than medical personnel, when a used needle and/or syringe is laid aside or discarded with a needle tip still exposed. This danger continues even when a used needle and/or syringe are placed in a disposal container. For instance, it is a routine medical procedure to use a device which cuts off the tip of an exposed needle so that it may not be re-used. However, this procedure still leaves exposed needle stubs and syringe parts which may be contaminated with infectious agents and with which persons may come into contact and be infected. Thus, it is not uncommon for discarded needle stubs to protrude through plastic garbage bags or other containers and present serious risk of a puncture wound to a person handling or otherwise coming into contact with the container. Similarly, even after used needles are removed from syringes and placed in sealed containers, the exposed syringes must also be placed in sealed containers to reduce the likelihood of infectious contact with personnel. Sanitary disposal of used needles and used syringes is an expensive and time consuming process and entails significant risk of exposure to infectious disease vectors.
A related problem is that of the dangers of exposing a needle to the atmosphere prior to its being used in giving an injection or withdrawing a body fluid. Not only is there danger of wounds to user personnel and patients from the exposed needle tip, but also there is the danger that the exposed needle will become contaminated by airborne or aerosol borne microbial and other contaminants and infect the patient eventually injected. This danger is particularly acute in hospitals and other medical treatment areas where strains of antibiotic-resistant microbes endemically contaminate the air and all exposed surfaces. Contact with non-sterile air is a certainty with conventional exposed needle syringe technology because, in this technology, needles are routinely exposed to the air or surfaces for some discrete amount of time during use. Also, in emergency use situations such as military combat, natural disasters, or industrial accidents, the unused needle may be left exposed to such contaminants by untrained, harried or inexperienced personnel.
Yet another common problem in conventional syringe/injection technology is that relating to improperly given injections. The differences in the rate which a needle must travel during insertion into and withdrawal from the subject's tissues and the rate at which a syringe piston must be operated in order to inject or aspirate fluid in a painless manner are substantial. The techniques of various medical personnel in using conventional syringes are varied. Techniques vary according to the position of the subject, how that portion of the subject's anatomy which is to be injected is held, and by the various individual techniques of medical personnel. This problem is particularly acute with respect to untrained or inexperienced personnel. When a needle is inserted too slowly, needless pain results. These problems are overwhelmingly due to the difficulty of operating a syringe and needle in a manner which appropriately varies the rates of needle insertion and withdrawal and the rates of fluid injection and aspiration.
An additional problem in the field is that of dosage management. For subjects who give themselves injections, either because they require regular doses of injected pharmaceuticals or because medical personnel are not available, it is critical to insure that dosages are correct. Diabetic subjects often find themselves in such situations, particularly diabetics who suffer from the related condition of blindness. Other blind people are similarly in need of a product which insures that both the type of medication and its dosage are correct for their specific needs. Similarly, soldiers in the field, travelers requiring regular injectable medications, and subjects in emergency situations where self-injection is necessary often have difficulty administering the proper dosage of a given drug and often have difficulty in using a conventional syringe. Such problems are also compounded by darkness or poor lighting conditions in battlefield, power failure, and other crisis or emergency situations.
It is well known in the medical injection field that, when administering a drug or other substance intramuscularly, an attempt is made to aspirate blood or other physiological fluid after insertion of the injection needle into a site thought to be suitable. Such an attempted aspiration is made in order to interrogate the injection site (i.e., essentially, as understood in the art the volume of tissue immediately adjacent to and in fluid communication with the open end of the needle) for the presence of blood, lymph, cerebrospinal fluid, or the like. This interrogation is made to insure that pharmaceutical substances or other fluids are not unintentionally injected inappropriately, e.g., into a blood vessel, lymph vessel or into cerebrospinal fluid. The inappropriate administration of a drug or other substance into a blood vessel, lymph vessel or cerebrospinal cavity could result in any of a number of adverse effects including nausea, unwanted toxicity, paralysis, neurological damage or even death. Moreover, the administration of pharmaceutical substances to inappropriate sites often results in attenuation or loss of the substance's desired, specific functional characteristics or activities. Thus, it is of paramount importance to insure that a needle used in administering a drug or other substance be inserted into an appropriate injection site.
For subjects injecting themselves at home, in emergency situations, or in combat, it is virtually impossible to perform the correct procedure. Similarly, personnel who are untrained in medical injection procedures but must give injections because of crisis or emergency situations are much more likely to incorrectly administer a substance, either by administering an incorrect dosage or administering by placing the needle so that its tip is positioned at an inappropriate site (e.g., so that the substance is injected directly into the blood stream rather than intramuscularly).
An example where a pharmaceutical substance must be delivered to an exact site is in the administration of certain chemotherapeutic drugs for the treatment of cancer. It is absolutely necessary that chemotherapeutic drugs be delivered to the exact target tissue. Exposure of some of these drugs to the skin or to the incorrect tissue or to the bloodstream may cause severe side effects. It is thus desirable to have a means for automatically interrogating the fluids in an injection device to insure that blood or other physiological fluids are not being inappropriately aspirated from a possible injection site into the device before drug is administered with the device. Thus, it would also be desirable to have a device which will automatically prevent injection of pharmaceuticals at an undesirable or inappropriate injection site. In other cases, however, it might be desirable or necessary to inject a drug into, for example, the bloodstream; then the interrogation would be to assure that a physiological fluid, such as blood, is aspirated into the injection device before using it to inject the drug.